The use of the perturbative methods for the sensi-tivity analysis in hyperthermic problems caused by the laser sources in the treatment of tumors / Uso de métodos perturbativos para análise de sensibi-lidade em problemas de hipertermia causada por fontes de laser usadas no tratamento de tumores

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The hyperthermic procedures available for therapeutic treatments of tumors can cause thermal damage in the adjacent living tissues and it is necessary to have an effective control systems. The temperature distribution inside the tissue must be controlled in order to avoid thermal damages to the healthy tissues in the neighborhood of the tumor. Numeri-cal simulation is an alternative way to know the temperature profile in the human body at some situations. The heat transfer analysis will be done by the Finite Volume Method (FVM) using unstructured meshes. Since there are no accurate data in the literature for the several parameters involved in the numerical simulation, a sensitivity analysis is required in order to identify the real influence of each parameter in the results. The computational costs of the sensitivity analysis of several parameters justify the use of the perturbative methods that are adopted mainly when there is no analytical solution for the problem or when the numerical solution is very expensive. The objective of this work is to evaluate the sensitivity analysis using the perturbative methods in hyperthermic problems originated by laser sources used in tumor treatments. The present work uses a previous thermal analysis that have analyzed the use of the laser probe Nd: YAG for the treatment of a duodenum tumor. For this purpose, the sensitivity calculations using the differential formalism of 1st and 2nd order will be done numerically. The thermal conductivity presented the major sensibility in the analyzed problem, followed by the specific mass and specific heat. Both per-turbative methods calculated the temperatures with accuracy. The 2nd order method pre-sented relative errors smaller than the 1st one, but its computational costs do not justify its use for this kind of application

ASSUNTO(S)

hyperthermia perturbative methods hipertermia laser thermophysi-cal properties energia nuclear métodos perturbativos laser engenharia nuclear propriedades termofísicas formalismo diferencial differential approach

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